Barbeque grills and smokers typically include a lower tub portion that is open at the top and a typically domed lid that mates with the open top of the lower tub. The tub portion typically is designed to contain coals, wood, or another heat source as well as to support a grill or other cooking surface or structure above the heat source. The lid is designed to mate with the lower tub to enclose the interior of the barbeque grill or smoker during cooking to improve cooking performance, provide for indirect cooking, etc. The lid and/or the tub of the barbeque grill or smoker may have adjustable vents formed therein, thereby to provide the operator with more control of the cooking temperature and process.
The lid on all grills and smokers must be able to be readily repositioned or removed to allow the operator access to the cooking surface within. In many cases the lid is not attached to the tub in any way, such that the lid is removed from the tub by simply lifting it up and away. Once removed, however, the operator must either hold the lid while accessing the cooking surface or find a place to set down a, in many cases, hot grill lid. Both options are inconvenient, unsanitary, and potentially dangerous. Thus, in some cases, grill or smoker lids will be attached to the lower tub using a hinge structure that allows the lid to be opened to access the grilling surface, without requiring that the lid be removed entirely. For example, a conventional favored method is to hinge the lid to the tub from the rear (12 o'clock position) allowing it to be opened from the front (6 o'clock position) by an attached handle.
Many grills and smokers are made of a relatively light weight metal material. However, ceramic grills and smokers are rapidly growing in popularity due to the many advantages obtained from the thick and heavy, high temperature ceramic materials they are made from. A grill or smoker made from ceramic material poses several unique design challenges relating to removal and replacement of the unusually heavy lid. That is, conventional methods of removing a lid from a grill or smoker tub or attaching a lid to the tub are even more inconvenient and ineffective when applied in the context of a ceramic grill or smoker having a very heavy lid.
Various present designs for attaching the lid of a grill or smoker to the lower tub portion thereof using a hinge structure differ mainly in the method employed of holding the lid in a desired open position. Common hinge designs utilize a single rear pivot axis located at the back of the grill or smoker (12 o'clock position) with support struts that are located on the sides of the grill or smoker (approximately in the 3 o'clock and 9 o'clock positions) and that extend between the lid and the lower tub portion. The support struts are locked in place by the operator's one remaining free hand as his other hand holds the lid in the open position. This design is awkward and somewhat dangerous as the operator has to place his hands or a suitable tool near the heat source to engage and disengage the struts each time the lid is opened or closed. The operator also has to lift the bulk of the lid's weight as it is pivoted open on the rear located hinge, which is particularly problematic for heavy ceramic grill lids.
Another rear hinge design utilized a torsion spring powered latching mechanism that automatically engaged when the lid was raised to the full open position. This design required one hand to open and two hands to close the lid, since the operator had to depress a release lever to disengage the latching mechanism while closing the lid with the opposite hand. Although such a design is safer and more user friendly than the earlier hinge design without an automatic latching mechanism, it also has its limitations. If an operator tried forcibly to close the lid without first depressing the release lever, the lid supporting bands that are used to attach the hinge mechanism to the ceramic lid would bend and the lid would fall out and break. An uninformed new operator or curious passerby could cause this to occur. This is an expensive and potentially dangerous occurrence. Furthermore, such a design does nothing to solve the problem of the operator having to lift the bulk of the lid's weight as it pivots on the rear located hinge.
U.S. Pat. No. 6,463,923 describes a rear single pivot axis design hinge mechanism for connecting a grill lid to the grill tub which utilizes an adjustable compression spring that forces a shaped latch tab against a roller. As the grill lid is opened, the shaped latch tab ramps onto the roller while it is compressing the spring until it reaches a shaped depression at the end of the latch tab that engages with the roller. This engagement action stops further opening of the grill lid and holds the lid at the desired opening angle. To close the lid, the operator pulls down on the lid forcing the depression in the latch tab to disengage the roller.
The amount of force required to close the lid is adjustable by changing the spring pressure with an adjusting bolt. Although this overall design is an improvement over previous designs, it also has several limitations. As with the previous designs, the operator has to lift the bulk of the lid's weight as it pivots on the rear located hinge, a particular problem with heavy ceramic grill lids. This hinging mechanism also requires proper maintenance and adjustment by the operator. If the roller isn't lubricated periodically, it will require excess force to engage and disengage the latching mechanism. This eventually results in the lid working its way out of the supporting bands that attach the lid to the hinge mechanism, causing the lid to fall to the ground (usually breaking), this is both dangerous and expensive. Improper adjustment of the spring tension can cause the lid to close on its own without warning, possibly causing personal injury. Improper adjustment of the spring pressure can also cause the lid to work its way out of the support bands and fall to the ground.
Other hinge mechanism designs exist that use a rear-pivoting hinge in conjunction with compression or extension springs that assist in lifting the weight of the lid from the tub while opening or closing it. Such assisted lift hinge mechanism designs pose several limitations as well. The springs used in these designs are at maximum strength when the lid is in the closed position. This typically doesn't allow the full weight of the lid to be applied to the gasket that seals air from leaking between the lower tub and the lid. Air leakage makes the grill temperature very difficult or impossible to control. Air leakage also allows the hot gasses from inside the grill to escape; this usually results in the gasket rapidly burning out, and that further compounds the leakage problem. The possibility of complete spring failure always exists, and springs gradually lose their strength over time in any case. Either of these scenarios could cause the lid to close on its own without warning, possible causing personal injury.
Therefore, what is needed is a new hinge mechanism for connecting the lid to the lower tub portion of a barbeque grill or smoker that will meet the following criteria: The hinge mechanism should safely maintain the lid in the open position without the use of springs, or any manual or automatically locking/unlocking latches or support struts. The hinge mechanism should allow all or nearly all of the lid's weight to bear on the gasket surfaces between the lid and the tub when in the closed position. The hinge mechanism should not require more effort from the operator to open or close the lid than current assisted lift hinge designs. The hinge mechanism should provide for limited adjustability for lid placement in relation to the base tub as compensation for ceramic manufacturing variances between the lid and the base tub concentricity and diameters.